A competition experiment of an invasive alien grass and two native species: are functionally similar species better competitors?

摘要: Invasive plant species often outcompete natives when colonizing new areas, but the mechanisms behind their success are unclear. The limiting similarity hypothesis predicts that functionally similar more prone to compete than dissimilar ones. This ecological assumption can assist in selection of a seed mixture for restoration disturbed sites, control opportunistic exotic plants at early stages establishment. We performed greenhouse experiment evaluate competition effects Stipa gigantea Link (Poaceae), species, and Lupinus luteus L. (Fabaceae), one, over invasive Cortaderia selloana (Schultes & Schultes fil.) Asch. Graebn (Poaceae). Our design included monospecific mixed pots three densities (one, two or four per pot) different invader (0, 25, 50, 75 100%). compared above-ground dry biomass, an indicator resource limitation growth, Specific Leaf Area (SLA), several indexes obtained from leaf reflectance spectrum, indicators physiological stress. showed strong intraspecific competition, with lower biomass higher densities. When grown was outcompeted by Stipa, which better unmixed pots, not affected Lupinus. Slight variations SLA photosynthetic performance were observed Cortaderia, demonstrating plasticity native did show any response. Based on our results, we suggest is weak competitor its advantage must lie other traits such as facility generate large amounts propagules efficiency seedling growth. Functionally may be adequate choice order plants.